Apparatus for applying sprayable materials to solid particles



Sept. 4, 1956 A. L. MOTTET APPARATUS FOR APPLYING SFRAYABLE MATERIALS TO SOLID PARTICLES 2 Sheets-Sheet 1 Filed July 13, 1953 INVENTOR. Hr I'hurL.Mof2 ef 'j Sept. 4, 1956 A. MOTTET 2,761,420

APPARATUS FOR APPLYING SPRAYABLE MATERIALS TO SOLID PARTICLES 2 Sheeis-Sheet 2 Filed July 15, 1953 INVENTOR. flrih UP 1.. M02716 i BY APPARATUS FOR APPLYING SPRAYABLE MATERIALS T SOLID PARTICLES Arthur L. Mottet, Longview, Wash., assignor to The Long-Bell Lumber Company, Longview, Wash., a cor- This invention relates to apparatus for applying sprayable materials to solid particles, particularly for applying resinous binders and/or size to wood particles preliminary to pressing them into fiberboard.

In the manufacture of fiberboard, wood first is reduced to the form of particles or fibrous elements. These then are mixed with a binder, usually a thermosetting phenolformaldehyde resin, and with a size such as wax or rosin, applied in the form of a liquid or a fine powder. The resulting mixture then is formed into a mat or felt and pressed into a fiberboard of the desired density.

In this sequence, the efiiciency of the operation in which the wood particles are mixed or coated with resin is critical to the commercial success of the process. In the first place, the resinous binder must be distributed uniformly over the surfaces of all of the wood particles in order to secure uniform bonding thereof during pressing. In the second place, the resinous binder must be deposited on or coated over the surfaces of the particles, with a minimum of impregnation. In view of the porous character of wood particles, this is a diflicult result to achieve, particularly where the resin is applied in liquid form. It is an important result, however, since the resinous binder which penetrates into the interior of the wood particles contributes little, if anything, to the strength of the adhesive bond and accordingly is wasted. This increases materially the cost of the final product.

It therefore is the general object of the present invention to provide apparatus for applying sprayable materials to solid particles, particularly for coating wood particles with resinous adhesives, which is eificient in distributing the applied material uniformly over the surfaces of the particles and in coating the particles, as opposed to impregnating them.

It is another object of this invention to provide apparatus for coating solid particles with adhesive liquids in which the liquid is applied uniformly to the solid particles without accumulating on the walls of the coating apparatus with accompanying formation of does or clumps which waste the liquid and produce defects in fiberboard products which may subsequently be made from the coated material.

Still another object of the present invention is the provision of apparatus for applying sprayable materials to solid particles which is readily and accurately adjustable to provide varying dwell or treating times Within the apparatus and selected ratios of applied material to solid particles.

it is a further object of this invention to provide apparatus for coating solid particles with liquids wherein the liquid is applied as a spray and provision is made for preventing the escape or leakage of the spray from the apparatus.

Still a further object of this invention is the provision of apparatus for applying sprayable material to solid in a three-stage mixing operation.

It is still a further object of this invention to provide hired States Patent 0 Patented Sept. 4, 1956 apparatus for applying sprayable materials to solid particles which apparatus is of high capacity though of relatively simple construction.

The manner in which the foregoing and other objects of the present invention are accomplished will be apparent from the following specification and claims considered together with the drawings, wherein:

Figure 1 is a view in side elevation of the presently described apparatus;

Figure 2 is a section view taken along the lines 2-2 of Figure 1;

Figure 3 is an elevational view looking into the apparatus from its infeed end; and

Figure 4 is a view in side elevation illustrating an alternate form of the presenting described apparatus.

Referring now more particularly to the drawings:

The apparatus of Figures 1-3 is mounted on a frame comprising the standards 10 having pivotally attached thereto through pivot pins 12 a supporting framework 14. Pivotal mounting of the framework enables adjustment of its inclination by suitable means such as the jack screw 16 fastened to the end remote from pivot pins 12. Although the angle of inclination is variable to suit the requirements of the contemplated operation, it may vary in the usual case from between about 1 to about 10 from the horizontal. In coating wood fiber with phenolic resin, an angle of inclination of about 6 has been found to be suitable.

A cylindrical drum 20 of suitable length and diameter is rotatably mounted on the supporting framework. On its interior surface are the spaced longitudinal bafiies 22 which may be in the form of corrugations of the material from which the drum is made. The upper end of the drum is open, but may be partially closed by means of cap ring 24 to prevent the escape of spray. Its lower end is partially sealed for the same reason, and to control the flow of air and fiber through the drum, by means of a transverse sealing baflie 26 supported by arms 28 extending inwardly from a lower cap piece 30. Baffle 26 assumes in general the configuration of the interior cross section of the drum, but is formed with an escape port 31 which is substantially aligned with the bed of solid material within the drum in the manner illustrated particularly in Figure 2.

Supporting and driving means are provided for rotatably supporting drum 20 and for driving it at the selected rate of rotation. To this end there are provided a pair of annular tires or flanges 32, 34 on the outside of the drum at the lower and upper ends thereof, respectively. Frame 14 has at its lower and upper ends Wheels 36, 38 rotatably mounted to turn in a horizontal plane. Tires 32, 34 straddle and engage wheels 36, 38 thereby preventing the longitudinal displacement of the drum while permitting its free rotation.

The Weight of the drum and its contents is carried by two pairs of wheels, a lower pair 40 mounted one on each side of the lower end of frame 14 and rotatable in a substantially vertical plane transversely to the longitudinal axis of the frame, and a similarly mounted upper pair 42 at the upper end of the frame.

At least one of wheels 40, 42 is powered to drive the drum. In the illustrated form, opposed ones of the wheel pairs are interconnected by a shaft 44 rotatably mounted in bearings 46, 48, 50. Shaft 44 carries a sprocket 52 which is driven through chain 54 from motor 56. Accordingly, the drum is rotated at a speed commensurate with the speed of the motor.

Means also are provided for feeding solid material, for example, wood particles, to the upper or infeed end of the apparatus. In the illustrated embodiment, the feed ing means comprises a chute 60, which enters the upper portion of the drum through the open end defined by cap ring 24. One or more spray heads 62 are stationed proximate, but below the chute, for example, on a bracket 64. This manner of positioning the spray heads relative to the chute is important because it makes possible the three-phase treatment of the solid material.

As is apparent particularly from Figure 3, the .spray of liquid or powdered adhesive or size emanating from heads 62 impinges upon the solid particles as they cascade downwardly from chute 60. This comprises the first stage. Then as the particles accumulate in the drum to form a bed therein, they are tumbled by the longitudinal, corrugated bafifles 22 and pass repeatedly through the spray or mist from the spray head. This com-prises the second stage.

The third stage of treating .the solid particles occurs after the solid particles leave the drum. As the mixture of coated particles and a residual fog from the spray pass through escape port 31 in sealing plate 26, they pass into conduit 66 which preferably is flexible to make possible the adjustable inclination of the apparatus.

Communicating with the conduit is a fan 68 and an air inlet 70. Fan 68 runs in a direction to exhaust air from the drum and in so doing draws in a proportionate amount of air from air inlet 70. This proportion is regulatable by means of damper 72. Heating means such as the heater 74 are interposed between air inlet 70 and conduit 66 to heat the air introduced into the apparatus to the desired temperature.

The foregoing system for evacuating the fibrous mixture from the drum therefore serves several purposes. In the first place, it permits the entry of a controlled amount of air and thereby controls the draft through drum 20 as required to prevent the escape of the spray from the open end thereof, without drawing it through at such a high rate as to prevent proper coating of the solid particles. In the second place, because of the restricted escape port 31 in bafie 26, it produces a region of high air velocity at the lower end of the drum, which pulls a uniform stream of fibrous material out of the drum and into conduit 66.

In the third place, it permits heating the coated particles to dry them or to advance any thermosetting resin with which they may be coated. In the fourth place, as noted above, it provides a third mixing stage wherein the solid particles are mixed with any residual spray and with the air which has been added through air inlet 78.

Alternate apparatus for applying sprayable materials to solid particles in accordance with the present invention is illustrated in Figure 4. This shares the foregoing features and advantages discussed in connection with the embodiment of Figures 1-3 but differs therefrom in the means employed in controlling the flow of air and material through the mixing drum.

As is apparent from the drawing, the apparatus of Figure 4 is mounted on a frame comprising a pair of standards 81 having pivotally attached thereto through pivot pins 82 a supporting framework 84. Accordingly, the inclination of the framework may be adjusted by suitable means such as the jack screw 86.

A cylindrical drum 90 of suitable length and diameter is rotatably mounted on the supporting framework. it preferably is corrugated, the corrugations 92 serving as longitudinal baffles on the interior surface of the drum. The upper end of the drum is open, but may be partially closed by means of a cap ring 94 to prevent the escape of spray. Its lower end is sealed by the cap .96 in a manner to be described below.

Supporting and driving means are provided for rotatably supporting drum 90 and for driving it at the selected rate of rotation. Accordingly there are provided a pair of annular tires or flanges 102, 104 on the outside of the drum at the lower and upper ends thereof, respectively. Frame '84 has at its lower and upper ends Wheels 106, 1% rotatably mounted to turn in a horizontal plane. Tires 102, 104, straddle and engage wheels 106, 188

thereby preventing the longitudinal displacement of the drum while permitting its free rotation.

The weight of the drum and its contents is carried by two pairs of wheels, a lower pair mounted one on each side of the lower end of frame 84 and rotatable in a substantially vertical plane transversely to the longitudinal axis of the frame, and a similarly mounted upper pair 112 at the upper end of the frame.

At least one of wheels '1-10, 112 is powered to drive the drum. In the illustrated form, opposed ones of the Wheel pairs are interconnected by a shaft 114 rotatably mounted in bearings 116, 118, 120. Shaft 114 carries a sprocket 122 which is driven through chain 124 from motor 126. Thus, the drum is rotated at a speed commensurate with the speed of the motor.

The feeding means employed for introducing wood particles or other solid material into the upper or infeed end of the apparatus comprises a chute which enters the upper portion of the drum through the open end defined by cap ring 94. One or more spray heads 132 are stationed proximate, but below the chute, for example on a bracket 134.

Thus, as in the case of the embodiment of Figures l-3 the spray of liquid or powdered adhesive or size emanating from spray heads 132 impinges upon the solid particles as they cascade downwardly from chute 130. This effectuates a preliminary coating of the solid particles with the spray material. Then as the particles accumulate in the drum and form a bed therein, they are tumbled by the longitudinal corrugations 92 of the drum and pass repeatedly through the spray or mist from the spray head. This eifectuates a secondary mixing of the materials.

The solid particles and sprayed materials are further mixed after leaving the outfeed end of the drum. As the particles leave the drum they .pass into a conduit 136 which leads to a rotary air valve 138. The latter contains a paddle wheel 140 driven by motor 142. It serves the dual function of sealing .off the lower end of the drum and of delivering fibers in a metered stream into the conduit 144. The latter conduit in turn is connected through the flexible coupling 146 to an exhaust fan 148 driven by motor 150 and communicating with the exhaust conduit 152.

Heated air at a predetermined temperature is supplied to conduit 144, being drawn by fan 148 from the atmosphere through the heater 154 and the sliding damper 156. As in the previously described embodiment, this serves the purpose of drying the particles, or of advancing the resin with which they are coated if either of these two results is desired.

Fan 148 also serves the useful function of controlling the flow of air through drum 90 in such a manner that there is a uniform, gentle flow of air through the drum in the feed direction. This prevents the escape of spray out of the open upper end of the drum, but Without interfering with the flow of solid particles therethrough.

To this end there is provided a conduit 158 which communicates at its upper end with cap 96 and at its lower end with conduit 144 containing the sprayed particles. A sliding damper 169 is associated with conduit 158 and accordingly provides a means of controlling the fiow of air through the drum. In this way the sprayed particles may be educted from the drum at a uniform rate and the spray prevented from escaping therefrom, insuring maximum utilization of the spray material and minimum hazard and inconvenience caused by escape of the spray from the apparatus.

Thus it will be apparent that the presently described apparatus in both of its illustrated embodiments coats the solid particles uniformly with a minimum penetration of the spray into the particles. Consequently, maximum benefit is obtained from a minimum quantity of sprayed material. Also, because the spray impinges at all times against the solid particles .rather than against the inner walls of the drum, there is little, if any, accumulation of spray material on the inner walls. This eliminates the possible formation of fiocs and clumps which would make the product leaving the coating apparatus non-uniform and which might interfere with its subsequent use. Furthermore, the apparatus is adjustable to accommodate a wide variety of sprayed materials, and is characterized by high capacity and simple design.

It is to be understood that the forms of my invention, herewith shown and described, are to be taken as preferred examples of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. Apparatus for coating particles of wood and like materials with liquids which comprises a rotatably mounted drum, motor means connected to the drum for driving it at a predetermined rate, tumbling bafile means within the drum, feed means at the infeed end of the drum for introducing a stream of particles of wood, spray means stationed proximate but below the feed means for applying liquid to the wood particles as they flow into the drum and are tumbled therein, a sealing bafile plate mounted independently of and across the lower end of the drum and forming an escape port substantially aligned with the bed of Wood particles within the drum, conduit means communicating with the lower end of the drum downstream from the escape port, an air inlet communicating with the conduit means, damper means Within the air inlet for controlling the flow of air therethrough, heating means associated with the air inlet for heating the air passing therethrough to a predetermined temperature, and fan means communicating with the conduit means downstream from the air inlet for educting the sprayed wood particles from the drum and for mixing them with hot air from the heating means.

2. Apparatus for coating particles of wood and like materials with liquids which comprises a rotatably mounted drum, motor means connected to the drum for driving it at a predetermined rate, tumbling bafiie means within the drum, feed means at the infeed end of the drum for introducing a stream of particles of wood, spray means stationed proximate but below the feed means for applying liquid to the Wood particles as they flow into the drum and are tumbled therein, conduit means communicating freely with the lower end of the drum, an air inlet communicating with the conduit means, damper means within the air inlet for controlling the flow of air therethrough, heating means associated with the air inlet for heating the air passing therethrough to a predetermined temperature, and fan means communicating with the conduit means downstream from the air inlet for educting the sprayed wood particles from the drum and for mixing them with hot air from the heating means.

3. Apparatus for coating particles of wood and like materials with liquids which comprises a rotatably mounted drum, motor means connected to the drum for driving it at a predetermined rate, humbling bafile means within the drum, feed means at the infeed end of the drum for introducing a stream of particles of wood, spray means stationed proximate but below the feed means for applying liquid to the wood particles as they flow into the drum and are tumbled therein, a sealing bafiie plate mounted independently of and across the lower end of the drum and forming an escape port substantially aligned with the bed of wood particles within the drum, conduit means communicating with the lower end of the drum downstream from the escape port, an air inlet communicating with the conduit means, damper means within the air inlet for controlling the flow of air therethrough, and fan means communicating with the conduit means downstream from the air inlet for educting the sprayed wood particles from the drum and for mixing them with air from the air inlet.

4. Apparatus for applying sprayable materials to solid particles which comprises a rotatably mounted drum, motor means connected to the drum for driving it at a predetermined rate, tumbling baflle means within the drum, feed means at the infeedend of the drum for introducing a stream of the solid particles, spray means stationed proximate but below the feed means for appilying sprayable material to the particles as they flow into the drum and are tumbled therein, a sealing baffle plate mounted independently of and across the lower end of the drum and forming an escape port substantially aligned with the bed of particles within the drum, conduit means communicating with the lower end of the drum downstream from the escape port, and fan means communicating with the conduit means for educting the sprayed particles from the drum.

5. Apparatus for applying sprayable materials to solid particles which comprises a rotatably mounted drum, motor means connected to the drum for driving it at a predetermined rate, longitudinal baflle means within the drum, feed means at the infeed end of the drum for introducing a stream of solid particles, spray means stationed proximate but below the feed means for spraying the solid particles as they flow into the drum and are tumbled by the longitudinal baffles therein, sealing means for sealing off the outfeed end of the drum, conduit means communicating freely with the lower end of the drum for educting the solid particles therefrom, and fan means communicating with the conduit means for educting the sprayed solid particles from the drum and for controlling the flow of air therethrough.

6. Apparatus for applying sprayable materials to solid particles which comprises a rotatably mounted drum, motor means connected to the drum for driving it at a predetermined rate, longitudinal bafile means within the drum, feed means at the infeed end of the drum for introducing a stream of solid particles thereinto, spray means stationed proximate but below the feed means for applying the sprayable material to the solid particles as they flow into the drum and are tumbled therein by the longitudinal bafiles, a cap on the outfeed end of the drum, first conduit means communicating with the lower portion of the outfeed end of the drum, rotary valve means in the first conduit means for metering the solid particles as they pass therethrough, second conduit means communicating with the first conduit means downstream from the rotary valve means, an air inlet in the second conduit means upstream from its point of communication with the first conduit means, third conduit means communicating with the cap piece and with the second conduit means downstream from the first conduit means, damper means in the third conduit means for controlling the flow of air therethrough, and fan means communicating with the second conduit means downstream from the first and third conduit means for conveying away the solid particles transmitted by the rotary valve and for pulling air through the second and third conduit means and through the drum.

7. Apparatus for coating particles of wood and like materials with liquids, which comprises a rotatably mounted drum, tumbling baffle means within the drum, feed means at the infeed end of the drum for introducing a stream of particles of wood, spray means stationed proximate but below the feed means for applying liquid to the wood particles as they flow into the drum and are tumbled therein, sealing baflle means mounted independently of and across the lower end of the drum and forming an escape port substantially aligned with the bed of wood particles within the drum, conduit means communicating freely with the lower end of the drum downstream from the escape port, an air inlet communicating with the conduit means, and a source of heated air communicating with the air inlet for mixing with the sprayed wood particles deposited in the conduit means 2,360,460 Williams Oct. 17, 1944 from the drum. 2,574,764 Smalley Nov. 13, 1951 2,592,231 Allstott Apr. 8, 1952, R f r nc s. Cite i the fil f this patent 2,599,852 McClain June, 10, 1952 UN STATES PATENTS 5 2,657,474 Bledsoe Nov. 3, 1953 1,283,486 Fay Nov. 5, 1-918 FOREIGN PATENTS 1,575,926 Mellie! Mal- 9., 9.2 652 390 Germany O 29 1937 2,197,792 Erickson Apr. 23, 1940 

7. APPARATUS FOR COATING PARTICLES OF WOOD AND LIKE MATERIALS WITH LIQUIDS, WHICH COMPRISES A ROTATABLY MOUNTED DRUM, TUMBLING BAFFLE MEANS WITHIN THE DRUM, FEED MEANS AT THE INFEED END OF THE DRUM FOR INTRODUCING A STREAM OF PARTICLES OF WOOD, SPRAY MEANS STATIONED PROXIMATE BUT BELOW THE FEED MEANS FOR APPLYING LIQUID TO THE WOOD PARTICLES AS THEY FLOW INTO THE DRUM AND ARE TUMBLED THEREIN, SEALING BAFFLE MEANS MOUNTED INDEPENDENTLY OF AND ACROSS THE LOWER END OF THE DRUM AND FORMING AN ESCAPE PORT SUBSTANTIALLY ALIGNED WITH THE BED OF WOOD PARTICLES WITHIN THE DRUM, CONDUIT MEANS COMMUNICATING FREELY WITH THE LOWER END OF THE DRUM DOWNSTREAM FROM THE ESCAPE PORT, AN AIR INLET COMMUNI- 